What are optional arguments in JavaScript Functions?



To declare optional function parameters in JavaScript, use the “default” arguments.

Example

You can try to run the following code to declare optional parameters −

<html>
   <body>
      <script>
         // default is set to 1
         function inc(val1, inc = 1) {
            return val1 + inc;
         }
         document.write(inc(10,10));
         document.write("<br>");
         document.write(inc(10));
      </script>
   </body>
</html>

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